Process and apparatus for cracking hydrocarbon oil



ug. 8, 1933. .x. D. SEGUY 92246 PROCESS AND APPARATUS FOR CRACKINGHYDROCARBON OILS Original FiledxMarch 16, 1923 Patented Aug. 8, 1933PROCESS AND APPARATUS FOR CRACKING HYDROCARBON OIL Jean D. Seguy,Chicago, Ill., assignor to The Universal Oil Products Company, Chicago,Ill., a Corporation of ASouth Dakota Application March 16, 1923, SerialNo. 625,456 Renewed March 14, 1929 6 Claims.

This invention relates to improvements in a process and apparatus forcracking hydrocarbon oils, and refers more particularly to a process inwhich the oil vapors are treated in successive stages to relieve them oftheir objectionable high boiling point fractions, and in addition, toseparate out the oil fractions which are outside a certain-predeterminedrange of boiling points ascertainable by temperatures maintained indifferent stages of the process.

Further objects of the invention are to utilize the heat in thepreheating of the oil to prevent loss through radiation, and furtherobjects as hereinafter specified. 1

35 The single figure is a diagrammatic side elevational vieW of theapparatus, partly in section.A

Referring to the drawing and describing the method of processing theoil, the charging stock is introduced from any convenient extraneoussource through the line 1, and is charged by means of the pump 2 throughthe line 3 and either introduced directly into the top of thedephlegmator 4 through the spray pipe 5, or by closing the valve 6 andopening the valve 'l the oil may be diverted through the line 8 througha jacketed coil 9 Where it is preheated prior to its being introduced tothe heating stage.

From the discharge end of the jacketed coil 9 the preheated oil flowsthrough the line 10, thence through a second preheating coil 11 fromwhich it is introduced into the line 12 which communicates with theheating coil 13. The heating coil is mounted in a furnace 14 which ispreferably of the side red type. After being raised to a conversiontemperature, the oil passes through the transfer line 15 into theexpansion or vaporizing chamber 16. This chamber is equipped with try'-cocks 17 for ascertaining the liquid level in the chamber; also Withresiduum dravvoff lines 18 controlled by valves 19 and a vapor line 20regulated by valve 21, through which the vapors evolved duringconversion are directed from the vaporizing chamber to the refluxingcolumn 4.

On being introduced to the dephlegmating or reuxing column 4 the vaporsrise, their travel being baiiied by obstructions or perforated pans 22positioned at intervalsL in the column. The vapors during their travelare also subjected to the dephlegmating effect of the raw oil introducedthrough the spray pipe 5. Any condensate separated from the vapors owsdown throughthe dephlegmator leg and is drawn off through the line 23'which communicates with the line 12, r whereby it is redelivered to theheating coil 13.

The vaporized portion on the other hand passes over through the line 24either to the water condensers 25 and 33 through connection 42, andthence to the receiver 34 as distillate, or by closing the valve 27 andopening the valve 28 in the line 29, the vapors may be introduced intothe bottom of a second reuxing column 30 through the spray pipe 31positioned in the bottom thereof. In a similar manner the dephlegmator30 is equipped with baliles or perforated pans 22, the vapors beingcaused to circulate through and about the pans in their passage to thetop of the column. The dephlegmated vapors uncondensed, on rising to thetop of the column 30 pass over through the line 32, and thence to thecondenser 33 and receiver 34, the valve 43 being closed.

The liquid condensate separated out in the refluxing column 30 is drawnoff from the lower leg of the column through the line 35, and may flowdirectly back to the heating coil 13 for retreatment, or by manipulationof the valves 36 and 37 in the line 38 this condensate may be chargedtotally or partially to the pressure pump 39 by means of which it iscirculated in the jacketed portion of the coil 9 around the incoming rawoil stock for the purpose of preheating the latter. This not onlypreheats the raw oil, but also serves to cool the reflux condensate,thus this cool reflux condensate may be directed through the line 40controlled by the valve 41 back into the top of the refluxing column 30.

A line 42 connects the condenser coil 25 With the condenser Vcoil 33 sothat the distillates may be combined in a single receiver or separatelycollected by manipulating properly valves 27, 28, 48 and 49. It will beunderstood that should the valve 43 in the line 42 be open and the valve49 in the line leading to the receiver 26 be closed, While the valve 27in the line 24 is open, all the distillate will be delivered to thereceiver 34 through the valve 48 and it will also be appreciated thatshould the valve 27 be open or partly opened, the valve 43 closed andthe valve 49 open, then certain of the vapors passingto the condenser25` Willy be condensed. therein and the distillate passed to the re'-ceiver 26. Condensate from condenser 33 will, when the valve 48 is open,collect inthe receiver 34. In some operations it may be desirable tobypass'the .dephlegmator 30. This may be accomplished by closing thevalve 28 and. opening the valve 27. The valve 43 is positioned in theline 42 for controlling the passage of the fluid oil constituents.Pressure on the system may be controlled by pressure relief valves 43"and 44 on the separate receivers, and the distillate drawn 01T throughthevalves 45 and 46 if desired. Difv ferential pressures may bemaintained upon the separate stages by regulation of the valvesinterposed in the connecting pipes.

As explained, in operation the raw 'oil is either preheated bycirculation through the jacketed coil surrounded by the hot reflux, ormay be introduced to the top, of the primary refluxing column. It isthen charged to the heating coil where the major portion of the heatingtakes place.

In place. of introducing the entire charging st ock to the top of thedephlegmator, portions of the oil may be introduced in this manner,while the rest may be circulated and preheated by means of the jacketedcoil, as explained. After being raised to a conversion temperature andpermitted to vaporize, selected portions of the vapors may be passedover and immediately condensed or diverted, and treated in the secondarydephlegmating stage and afterwards condensed and collected in theseparate receiving tank 34, or portions of the vapors may be passed overto the condenser coil 25 and portions diverted for further treatment inthe column 30 as desired. In any case, the processing of the oil may beso regulated that distillates of the desired character may be collectedin the separate receiving tanks, or blended in a single receiving tankthrough the communication between the condenser coils.

Thermo couples 47 are positioned in the different stages of theapparatus for ascertaining the temperatures maintained therein, 'Ihesetemperature recording devices are particularly important in the top ofthe dephlegmating column where it is important to the character of thedistillate collected to maintain temperatures between a predeterminedrange.

The apparatus may be also utilized to relieve the oil of any moisturecontent for when the raw charging stock is` introduced to the top of thedephlegmating column, the temperature is there suliicient to separateout any water contained in the oil which will pass over immediately andbe collected as liquid in the receiving tank, where it may be drawn oir.

By treating Mid-Continent gas oil of approximately 32 Baum, yields offrom 40% to 60% -an elongated passageway disposed within a furnace`wherein the oil is subjected to conversion conditions of heatandpressure, in directing the heated oil constituents from saidenlongated passageway into an enlarged reacting zone, in passing theevolved vapors kto a primary dephlegmator, in passing the vaporsuncondensed in said primary dephlegmator through a second zone ofdephlegmation, in placing a streamer raw oil under a mechanicalpressure, in splitting said stream of raw oil, in directing one portionthereof into said lprimary dephlegmator to aid in the dephlegmation ofthe evolved vapors and to preheat said portion of the: raw oil, indirecting the other portion of said split stream of raw oil through azone of heat interchange with reux .condensate withdrawn from saidsecond zone of dephlegmation to preheat this portion of the split streamof raw oil, in then uniting the pre- L92r24e .heated portions of saidsplit stream, and in introducing them together with reflux condensate.from said primary dephlegmator to the inlet side of said elongatedpassageway, and in maintaining regulated superatmospheric pressure onthe oil undergoing conversion.'

2. A process for the heat treatment of hydrocarbon oils to producegasoline-like distillates suitable for use as motor fuels, whichconsists in passing a stream of oil through a heating coil wherein saidoil is heated to a cracking temperature, delivering the oil to anenlarged zone oif reaction, wherein vapors are evolved from the heatedoil, passing ev olved vapors through a series of dephlegmators, passinga stream of charging stock to the rst of said dephlegmators, recyclingreflux condensate from and to the second of said dephlegmators, coolingsaid recycle reflux condensate by heat interchange with a second streamof charging stock, passing the charging stock from the heat exchangetogether with charging stock and reflux condensate from said firstdephlegmator to the heating coil.

3. Apparatus for heat treatment of hydrocarbon oils, comprising incombination, means for heating the oil to a cracking temperature, anenlarged reaction chamber, means for passing the heated oil from saidmeans to said chamber, a dephlegmator, means for taking off vapors fromsaid chamber and passing them to said dephlegmator, a seconddephlegmator, means forpassing uncondensed vapors from the firstdephlegmator to the second, means for maintaining cyclic circulation ofcooling medium in the second dephlegmator, means for supplying a dividedstream of charging oil for the process under pressure, means for passingone portion of said stream to the first dephlegmator, means for passingthe other portion of the divided stream in heat interchange relationwith said cyclic cooling medium, and means for reuniting the streams andpassing them to the heating means.

4. A process of oil conversion, consisting in passing a restrictedstream of oil through a con` tinuous elongated passageway where said oilis 1 0 heated to a cracking temperature, in transferring the heated oilconstituents to an enlarged reaction zone where conversion occurs, inpreventing thegreturn of any unvaporized oil from said reaction zone tosaid elongated passageway, in

discharging generated vapors to a reiiux condenser, in placing a streamof charging stock under a forced pressure, in splitting said stream andin directing a section thereof to said reux condenser to condenseinsulciently cracked vapors and to heat said section of the stream,directing the other section of said split stream while out of contactwith the vapors undergoing reflux condensation into heat interchangewith reflux condensate produced in the process to preheat saidlast-mentioned section of the split stream, and to cool such refluxcondensate, then bringthe, cooled reflux condensate into direct contactand countercurrent flow with vapors undergoing reiiux condensation inthe process and in uniting the preheated split sections of said streamof charging stock together with reuxcondensate formed in said refluxcondenser prior to the entrance of the o'il to the inlet side of saidelongated passageway, and in maintaining a superatmospheric pressure onthe oil undergoing conversion. 5. A hydrocarbon oil cracking processwhich comprises subjecting the oil to cracking conditions of'temperature and pressure "in a heating zone, separating vapors fromunvaporized oil..

passing the vapors to a primary dephiegmating zone and cooling the sametherein by heat `er.- change with charging oil for the process therebyforming primary reux condensate and preheating the charging oil,subjecting the uncondensed vapors to secondary dephlegmation therebyforming secondary reflux condensate, preheating additional charging oilfor the process by heat exchange with a portion of said secondary reduxcondensate, returning the thus cooled portion of the secondary refluxcondensate to the secondary dephlegmation as a dephlegmating mediumtherefor, and supplying another portion of said secondary refluxcondensate in admixture with the preheated charging oil and primary reuxcondensate to said heating zone.

6. A hydrocarbon oil cracking process which comprises subjecting the oil to cracking conditions ture to said heating zone.

of temperature and pressure in a heating zone, separating vapors fromunvaporized cil, subjecting the vapors to primary dephlegmation therebyforming primary reux condensate, subjecting the uncondensed vapors tosecondary dephlegmation thereby forming secondary reflux condensate,cooling a portion of said secondary reux condensate by heat exchangewith charging oil for the process thereby preheating the latter,utilizing the thus cooled'portion of the secondary reui: condensate asthe dephlegmating medium for said secondary dephlegmation, combininganother portion of said secondary reux condensate With the preheatedcharging oil and primary reux condensate, and supplying the resultantmix- Jnan n. snoer,

